Introduction: The use of chemical exposure risk assessment methods is a suitable solution to check the exposure of employees to chemicals. Therefore, the risk of occupational exposure of workers in the mining industry to crystalline silica was assessed with four methods.Material and Methods: This descriptive-analytical study was conducted in the active mines of Alborz province in the period of 2017-2018. Five steps were used to implement the current research.Result: The total mean of crystalline silica was equal to 0.052 ± 0.03 (mg/m3) in the range of 0.01-0.32, which was higher than the recommended standard limit. The death rate due to lung cancer was calculated as 14.74 people per 1000 people in range of 4.88-42.09. The risk rate of silicosis was in range of 1- 6.22 person per 1000 people. Semi-quantitative risk assessment was obtained at a high level. The results of pulmonary function indicators showed that there was a significant difference between the two groups in pulmonary parameters FEV1%-FVC% PEF%, And mine workers had lower capacities than food factory workers (control group). We found that occupational exposure to crystalline silica can predict the variables of FEV1/FVC% and FEV1%. Conclusion: It seems that the current occupational health engineering strategies were not enough to safeguard workers. It should be noted that all these conditions were related to semi-active mines. If the mining activity reaches its maximum capacity, the situation will become much more dangerous. It is necessary to control the exposure of workers to crystalline silica dust in mines.